Messages in this thread | | | Date | Mon, 4 Jun 2012 00:59:04 +0100 | From | Al Viro <> | Subject | Re: processes hung after sys_renameat, and 'missing' processes |
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On Mon, Jun 04, 2012 at 12:40:42AM +0100, Al Viro wrote: > On Mon, Jun 04, 2012 at 12:28:20AM +0100, Al Viro wrote: > > > Everything in lock_rename() appears to be at lock_rename+0x3e. Unless > > there's a really huge amount of filesystems on that box, this has to > > be > > mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); > > and everything on that sucker is not holding any locks yet. IOW, that's > > the tail hanging off whatever deadlock is there. > > Er... After another look, probably not - it's ->s_vfs_rename_mutex, > so we are seeing one cross-directory rename stuck on something with > all subsequent ones blocked on attempt to grab said mutex. > > The interesting one is the guy stuck at lock_rename+0xc9/0xf0, everything > else in lock_rename() is the consequence.
BTW, another suspicious patch is d_splice_alias() one; note that if we _ever_ pick a dentry that isn't disconnected, we are deeply fucked. d_move() without the old parent locked is a Bad Thing(tm). I don't see how that could've triggered without another bug somewhere, but what's happening in d_splice_alias() right now is wrong.
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